Telephone system



Ot 9,.-.1945- A. HUBBARD TELEP'HONE SYSTEM Filed July 3, 1943 2 Sheets-Sheet l m .mi

,zou S ,SG n $6.5 n. @1.35. s s

A TTORNEV Oct. 9; 1945. F A, HUBBARD 2,386,609

` TELEPHONE SYSTEM.

Filed July 3, 1943 l 2 sheets-sheet 2 LINE t LINE/0 NIH mvg/v To@ F. A. HUBBARD gyrp. M

A TTORNFV Fig. Sslsiows yone Patented Oct. 9, 1945 diilalrlarly)i STAT-Es PATENT QFFICE l 'f 2,336,699 .f '.f l

Y l n rELEPHoNE'sYsTEM -i l I hFrancisjA.' Hubbard, MaplcwoodQN. J.,wasisignor v -Y to Bell'Telephne Laboratories, Incorporated, L'New York, N.'Y., a corporation oftNe'w Yorkr' Application July 3, 1943, Serial-'Nog 493,410 A.2 claims. (C1. 179-99);

' ,This Y invention relates to signaling andf com- A`mun'ica'tion systems andparticularly to telephone s'ystemsof the keyf calling type.` v y l :'.Keycallin'g systems have been devised .pri- "r`r 1:}trily` toprovide facilities vwhereby telephone corinectioiisr between a 'calling subscribers .line fand any of 'a group of frequentlycalled lines may A befcompleted expeditiously and with a minimum fofeio'rt ,on thepartof the calling subscriber.

Such systemsare'characterized by a subscribers telephone' set which 'is provided with a .plurality 'of individually operable keys or key buttonsheach jffwhihfmayg'be assigned to' aparticular one of.; thefir'eduently called lines. However, such a Referring` rstfto'Fi'g. 1 together with Figs. 3 and 4, the telephone'set includes the handsetA |00, cradle '|0|, coil |02, ringer |03 and condenser |04. -In, addition',the'telephone'set is equipped with a set often keys lto |20,- a setof Ufbars |05to |09 and a set of rotatalole cams|2| to |21 with a'driving magnet |28. f w

On each key is mounted a camming collar, forl the -collars is la plate |32 having openings |33,

the sides of which slope' atthe same angle as the sides of the collars. -The plate-|32is slidably 'telephone set may also be used, with suitable\15 l receiving equipment vto*v control the establishment di ordinary telephone connections.

ff ATheke'y calling, executive type system, in order rtobtai a' suciently larga code, has required jcomplex mechanisms for generating, timing and spacing the code pulses. l -v In accordance with the present invention, alternating current supplied fromthe receiving equipnient ,is employed,v said current controlling the .timingand spacing oi the pulses.

ft'rat'ion fof the code.

rIYhese V@other features, of the inventionvwill be mereapparent from f@consideration of the following; descriptionninr connection with the -y.1.`?'WPgS,if.1,WhCh y f 4is a schematic showing of the equipment atthe Ycalling/station and the circuits thereat;

f pulses'; Y

l key ready for operation;

Fig. 4 shows the key locking arrangement;

Y Fig. 5 is Ya time-currentV diagram for one code ;'yizlmdv Fig. 6'is a tableindicatingthe bars at4 the calling; station and register relays at` the receiving station operated in response to the depression of ""eachkey.,

` Fora disclosure of a' key calling telephoneset shows the circuits for receiving the code mounted in any desirable manner and is normally held in the positionl shown, bythe action ofthe strong spring rr|08 rresting `against stop |65. When the handset |00 is'removed from Ithe cradle |0|, spring'MB is-disengaged from plate |32 and plate |32 moves under the' control Yof the vweaker spring 34 until the openings comeinto Vregistration-With the collars on keys V| .to |20, as shown in Fig. 3. The position of :plate |32 Vat this time is fixed by pinwlll. .When a key, for example, key is Y .,25 `More specifically the code is obtained bysupoperated, lthe .collar |30. enters the opening |33 movingthe plateA |32 to: theleit. Whenvthe key is.completelydepressed, .plate |32 passes beyond yshou1der,|3| and ,is then drawn back by spring s. position, openings which registered with'the collars of the otherA keys following the removal of the handset fromthe cradle are displacedsuiciently so that the collars would strikethe top L of Ythe plate/andino other key can' be depressed (see Fig. 4). f. y

Belowthe plate |32, each key terminatesfin a disc-like member |35 ,which is in position'to act on extensions of' oneor more of the U-bars Y|05 to |08. -The U-bars I05to v|09 are resiliently mounted soY that they tend to return to the, posifshwing a typical arrangement of the keys and ,bars reference may be made to applicantscopending application `Serial No. 479,417, iiled yMarchlL. 1943, which became Patent No.

.tion shown and-to return a'depressed key to normal whenr released by plate |32. I The'upward extensions on the U-bars |05 to |08 are provided according to thecode. set forth in Fig. 6. Bar |09 is acted on by studs on all the other bars lSo as to be moved whenever any key and its associated code U-bars are operated.

Each of the code bars r|05.to |08 has a single operating arm to which is iiexibly mounted an operating lever controlled by one of the cam wheels |24 toA |21. For example, U-bar |05 has an arm |36 to which lever |38 is fastened by means of the flat spring |31. 0n lever |38 is a stud |38 which extends into the path of rotation of the projection on cam Wheel |21 only if bar |55 is depressed. With bar |05 depressed the end of lever |38 overlaps the pin on bar |40 and the rotation of cam wheel |21 acting through stud |38 causes bar |40 to move to the right for a purpose to" berdiscussedflater. "Bar |40is""='slidably mounted by means ofpins |4| and *|42-andslo`ts |43 and |44 and is held in the position shown by means of spring |45. l

driven by means of magnet |28 and ratchetivhel |2| which also drive control'canr-wheels |72 s"and |23. The functions of canfuheelse" A W23 will be explained in connection^vvith`th `fihptions of the substation circuits. rseriesi-'Withgjtljie Winding of magnet |28 are rectiiiers |46 and 41 so poled that current can ow through'th'tvind- V'-inggof magnet `|28 1only in' one: direction. A A a Whenthesubscriber Wishes to initiatek va call he i will remove the handset; 00 frorrithe cradle A| 0 ji thereby permittinglever,V |49 to ijlotatevlaround pin |50 and remove spring 43-from `pla-te 1| 32,. so that "the openings ofvplate |532 register with the collars |30, etc. on the keys. K

Y The release of thercradle |0| also causes any f suitable equipment atfthe `receiving, circuit to completeal circuit fromthe secondary rvilinding of coil-200at the receivingstation, over contactl 2 of relay 20|, tip `conductor 202.norma1-condtact -,|f5| ,7through the .transmitter of handset |100, -4"switchhook contact -|52;;right Winding of repeat- -ingcoil-f|02yto ring -conduct or-203', contact 5 of 'relay 28|; throughrect`ier`204-inparallel lWith jr'ectier `205 fand-relayv 206= and vthrough `fr ectiiier f; i201J inparallel'; 'vvith= rectifier g20 8'; and re1ay--209 "hackto thetsecond-ary` Winding of coilrZDQ.

.'tlan'smitted through coil 200 tothe -circuitnabove -"traced but isineiectiveuntilpne oftheykeys "ftd llf2fhas'been depressed. i @ny the 'fother hand, i if thisfarrangementf were lassociated '-Wth ,av-'centrai oiil'cecircuitv usingcomrnonfserrders, fthef'pre- *mature operation-fof a `lteyfwouldffheiiheifective 'until the is'ource fof f alternating 'currentffhasbeen connected-tothe line.

, Jihetline' circuitrnow extendsffromcpnductor 202, over contact |51, through rectifier |:146`;i Winding of magnet |28 to vconductor2i03. 1Pif-palralle] -:f'path extends from contact |51 overfcorrtact'fil-55| throgughrectier |41to conductor 203.` H'Rectiers |46 "and: |41 are-so-poled thatfpositivehalf `cycles :ofthe alternating current pass through `"the-Winding of rnagnert 1| 28 while negative f haiti-'cycles go by. Wayrof rectifier |141 andicontact|f53.

made in six steps requiringfsx cycles'fofthe 4"alterhating current.y "AtftheWeginninge or the'first `step lever r| 5l8fr'iro13s-u into f'the fdepressi'ononfcam 1 wheeli22'causingstud |'59ito open contact-'|53 s0' thatthe hegativerhalf`cycle 1Which follows :is --suppi'essed as astartsi'gnal.j ToWardlthefend of fthe: rst "step'cam lf2 3 'operateslevef |56 "t lock lever |55 and hold it down until the end of revolution, thereby insuring the restoration of the cani wheels to normal.

The next step of ratchet Wheel |2| in response to the second positive half cycle brings the pro- 5 iection on cam wheel |24 into engagement with stud |60, since U-bar |88 was depressed, thereby #moving bar '|'40 `to the rightzand'opening the contact |53 bynieans of *stud ."|B|.""'f['lierefore, the rst of the code negative half cycles is suppressed. 10. At the third step the projection on cam Wheel |25 is in a horizontal position, but, since U-bar "*"|01vvas not depressed the cam Wheel |25 is in- T eifecti've-'and thesecond negative half cycle passes evercontact|-53 to the receiving circuit.

:H15 L .-cAtthefouthfeIrid fifth steps, respectively, cam

"anately fand:fineirectua11y.

f Asset fOr-tn 'infthel-nes'eriptinn (if-'Figli 1i-*me first step of the cam y/tvheels "fc` llotvifng4 `the ilde- 75 pression of a key causes `the suppression of the relay 29, right back contact oi relay 206, normal contact 2| 1, controlled by brush arm 212, winding of stepping magnet 213 to ground. Magnet 213 rotates brush 212 one step.l The movement of .brush 212 opens normal contact 211, thereby opening the original energizing circuit of magnet 2 I 3 and closing at contact 2 I 5 an alternative cir- Relay 2 18. guards. .the receiving .circuit against the'abnor'mal advance .fof brush arrn212 to its second position. Relay 2118 isslow to operateand cuit for magnet 213 which is completed at the next positive half cycle, from battery over the front contact of relay 209, and contact 215 tothe winding of magnet 213 and ground. Magnet 213 advances brush 212 to the-second terminal.

According to the foregoing description of Fig. 1J the code for the digit 0` was transmitted which calls for the suppression of the first, third and fourth half cycles. Therefore, during the first negative half cycle of the code, relay 206 is not operated and a circuit is closed from battery over the back contact of relay 206, brush 212 and its second terminal, winding of register relay 221 to ground.

' Relay 209, in response to the ensuing positiveV half cycle, causes the advance of brush 212 to its e third terminal. Since the 'second negative half cycle is not suppressed, relay 206 operates opening the register operating circuit, leaving register relay 222 unoperated.

Brush 212 is advanced to its fourth and fth terminals by the third and fourth positive half cycles and, since the third and fourth negative half cycles are suppressed, relay 206 does not operate during either half cycle and registerrelays 223 and 224 are operated. Relays 221, 223 ii 224 lock to battery over -contact 6 of relay In response to the fifth positive half cycle, brush 212 is moved into position to close contact 214, thereby completing a circuit from ground over contact 214, through the upper winding of relay 201 to battery, Relay-201 disconnects the alternating -current source from the rwinding of repeating coil 102, conductor 203,

lower winding and contact 4 of relay 201s conductor 211 to ground. Relay 201, at its contact 1, connects battery to the windings of the line selecting relays 231 to 240. With register relays 221, 223.and 224 operated the circuit of relay 240 is completed over contact 5 of relay 224, contact 3 of relay 223, contact 2 of relay 222 and contact 14 of relay 221 to ground. Relay 240 locks to ground at its left contact and at its right contact extends conductors 216 land l21'1 to line No. 10. Any convenientI means may be employed for signaling the called line. Relays 240 and 201 remain operated throughout the conversation. When handset 100 is restored to the cradle, the locking circuit of relay 201 is opened, in turn opening the locking circuit of relay 240, restoring both to normal.

The operation of relay 201 also opens contact 6 after a delay, releasing the register relays 221 to zz4. when brush 212 steps beyond Contact 214 the switch is again normal and off-normal contact 215 is opened by the next brush, Which takes up the function of brush 212.

cannot operate during the normal operation of the receiving circuit. If, for any reason, brush 212 should be advanced toits second ypositionland remain there, when relay 206 is no longeroperated by the alternating current, relay 218 operates in a circuit from ground through the winding of relay 218, brush 212 in its second position, to battery at the back contact of relay 206. With relay 218 operated, a self-interrupting circuit is closed for magnet 213 from battery over the front contact of relay 218, backvcontact of magnet 2,13,

off-normal contact 215 through the winding of' magnet 213 to ground, thereby stepping the switch back vto normal where the opening of offnormal contact 215 brings the switch to rest. At each operation of magnet 213 a circuit is closed from battery over the front contact of relay 218 and the front contact of magnet 213 to the winding of relay 213 and ground to hold relay 218 operated until the switch is normal. s

TheV particular advantages of this present code transmitting and receiving arrangement as compared to ones previously proposed arethat it requires no timing mechanism at the key-set; that it employs a minimum number of contacts in the code transmitting circuit and that the start of the code transmission is under the control of the current supplied from the receiving equipment so that no signal can be transmitted before the means for receiving it is ready.

What is claimed is:

l. In a telephone system, a calling substation,

-called substations, transmitting means at said substations, selecting equipment common to said substations, means for transmitting the designation of a called substation from said calling substation to said selecting equipment comprising a loop circuit connecting said transmitting means and said selecting equipment, means for applying alternating current to said loop circuit, distributing means in said transmitting means, distributing means at said selectingrequipment, means to simultaneously drive said distributing means in response to a plurality of half cycles of said alternating current having one polarity, and means under the control of the distributing means at said transmitting means to suppress the intermediate half cycles of said alternating current, a. register comprising a plurality lof relays at said selecting equipment, means under the control of the distributing -means at said selecting equipment or'placing said relays successively under the control of said transmitting means during said intermediate half cycles, and means operated by said register to connect said calling substation with the called substation.

2. In a telephone system, a calling substation, called substations, transmitting means at said substations, selecting equipment common to said substations, means for transmitting the designation of a called substation from said calling substation to said selecting equipment comprising a loop circuit connecting said transmitting means and said selecting equipment, means for applying alternating current to said loop circuit, distributing means in said transmitting means, distributing means at said selecting equipment, means to simultaneously drive said distributing means in response to half cycles of said alternating current 

